1. Field of the Invention
This invention relates to a multi-functional flow control valve for water treatment systems.
2. Description of the Prior Art
All existing industrial and household water treatment systems depend on switching function of multi-functional flow control valves for the purposes of softening, purification, backwash and regeneration of effluent. Typical of the valves on current market are Fleck valves and Autotrol valves. The Fleck valve, produced by Pentair, Inc., USA, has several layers of seal rings in a valve body thereof, which are separated by several working of plastics, thereby allowing space therebetween. The seal rings are sealed against the valve body on an external side thereof and against a cylinder encapsulated piston on an internal side thereof. The encapsulated piston is drawn up and down and positioned at different positions to form different flow channels. That is, the performance of the multi-port valve is realized by the encapsulated piston being placed at different positions along the axis. The Autotrol valve, produced by Autotrol Corporation, also in USA, has several valves arranged along a band in a valve body thereof. A cam rotor axis with several cams at different angles is worked by an engine. As the cam rotor axis rotates, the cams at different angles are open to certain ports but closed to others, thereby to realize different flow channels and the desired functions.
Apparently, some types of multi-functional flow control valves exist. One combines several valves into one valve body, which results in a more complicated structure, difficulty in manufacturing, bigger size and inconvenience in installation. Another type of flow control valves connects several external valves and the flow is controlled by opening and closing different valves in different positions. This type is difficult to install and inconvenient to operate. The third type features the movements of the encapsulated piston in the sealed cavity. The flow is controlled and directed by locating the encapsulated piston in different positions. However, the problem with this structure is that the flows in those channels are easily mixed and thus undermine the treatment effect.